Java中json与javaBean几种互转的讲解

public class Student {
  //姓名
  private String name;
  //年龄
  private String age;
  //住址
  private String address;
  public String getName() {
  return name;
  }
  public void setName(String name) {
  this.name = name;
  }
  public String getAge() {
  return age;
  }
  public void setAge(String age) {
  this.age = age;
  }
  public String getAddress() {
  return address;
  }
  public void setAddress(String address) {
  this.address = address;
  }
  @Override
  public String toString() {
  return "Student [name=" + name + ", age=" + age + ", address="
  + address + "]";
  }
}

public static void convertObject() {
    Student stu=new Student();
    stu.setName("JSON");
    stu.setAge("23");
    stu.setAddress("北京市西城区");
    //1、使用JSONObject
    JSONObject json = JSONObject.fromObject(stu);
    //2、使用JSONArray
    JSONArray array=JSONArray.fromObject(stu);
    String strJson=json.toString();
    String strArray=array.toString();
    System.out.println("strJson:"+strJson);
    System.out.println("strArray:"+strArray);
}

public static void jsonStrToJava(){
    //定义两种不同格式的字符串
    String objectStr="{\"name\":\"JSON\",\"age\":\"24\",\"address\":\"北京市西城区\"}";
    String arrayStr="[{\"name\":\"JSON\",\"age\":\"24\",\"address\":\"北京市西城区\"}]";
    //1、使用JSONObject
    JSONObject jsonObject=JSONObject.fromObject(objectStr);
    Student stu=(Student)JSONObject.toBean(jsonObject, Student.class);
    //2、使用JSONArray
    JSONArray jsonArray=JSONArray.fromObject(arrayStr);
    //获得jsonArray的第一个元素
    Object o=jsonArray.get(0);
    JSONObject jsonObject2=JSONObject.fromObject(o);
    Student stu2=(Student)JSONObject.toBean(jsonObject2, Student.class);
    System.out.println("stu:"+stu);
    System.out.println("stu2:"+stu2);
}

public static void convertListObject() {
    Student stu=new Student();
    stu.setName("JSON");
    stu.setAge("23");
    stu.setAddress("北京市西城区");
    Student stu2=new Student();
    stu2.setName("JSON2");
    stu2.setAge("23");
    stu2.setAddress("北京市西城区");
    //注意如果是list多个对象比需要使用JSONArray
    JSONArray array=JSONArray.fromObject(stu);
    String strArray=array.toString();
    System.out.println("strArray:"+strArray);
}

public static void jsonToList(){
    String arrayStr="[{\"name\":\"JSON\",\"age\":\"24\",\"address\":\"北京市西城区\"},{\"name\":\"JSON2\",\"age\":\"24\",\"address\":\"北京市西城区\"}]";
    //转化为list
    List<Student> list2=(List<Student>)JSONArray.toList(JSONArray.fromObject(arrayStr), Student.class);
    for (Student stu : list2) {
    System.out.println(stu);
    }
    //转化为数组
    Student[] ss =(Student[])JSONArray.toArray(JSONArray.fromObject(arrayStr),Student.class);
    for (Student student : ss) {
    System.out.println(student);
    }
}

public static void mapToJSON(){
    Student stu=new Student();
    stu.setName("JSON");
    stu.setAge("23");
    stu.setAddress("中国上海");
    Map<String,Student> map=new HashMap<String,Student>();
    map.put("first", stu);
    //1、JSONObject
    JSONObject mapObject=JSONObject.fromObject(map);
    System.out.println("mapObject:"+mapObject.toString());
    //2、JSONArray
    JSONArray mapArray=JSONArray.fromObject(map);
    System.out.println("mapArray:"+mapArray.toString());
}

public static void jsonToMap(){
  String strObject="{\"first\":{\"address\":\"中国上海\",\"age\":\"23\",\"name\":\"JSON\"}}";
  //JSONObject
  JSONObject jsonObject=JSONObject.fromObject(strObject);
  Map map=new HashMap();
  map.put("first", Student.class);
  //使用了toBean方法，需要三个参数
  MyBean my=(MyBean)JSONObject.toBean(jsonObject, MyBean.class, map);
  System.out.println(my.getFirst());
}